russell
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Post by russell on Mar 21, 2009 19:35:00 GMT
In view of the recent discussions on boiler construction, approval, safety, insurance etc., I'd like to pose a question:
Does anyone have knowledge of accidents caused by boilers in steam models in, say, the last 20 years? It would be interesting to know how many accidents occurred both before and after the EU directive came into force.
Russell.
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Post by alanstepney on Mar 21, 2009 20:06:59 GMT
There have been a few, a very few, boiler accidents with model boilers over the years.
Because there are so few, our insurance cost is minimal.
I dont think that anything has really changed with the EU directive as, for most people, it made no difference.
Whilst I have some details of failures, or rather, alleged failures, there hasnt been anything that was really serious.
Potentially serious perhaps, but nothing more.
The last boiler failure that resulted in serious injury that I have been able to trace was in 1927.
Thus "our" models have a far better safety record than full size ones.
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Post by stantheman on Mar 21, 2009 20:27:11 GMT
Part of the discussions that took place some years ago, I believe, was the extremely good record of boiler safety and the good self policing over many years within the hobby. All of this resulted in the virtual freedom to continue building 'our own boilers, to proven design in many cases', with club boiler inspectors carrying out the task of certification.
I like the comments from one of my own club members who says, 'It's your wedding tackle that is nearest to any problems with your boiler', although maybe not using those exact words!
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Post by baggo on Mar 21, 2009 21:38:40 GMT
The only one I can recall reading in ME involved a small boiler in a model steam boat and that was in the 20's or the 30's. Even that did not involve any injury so far as I remember. I agree with Stan's comment - I'm the one sitting almost on top of the boiler so I'm not going to take any chances with it's construction ;D However, I have heard some hair raising tales involving locos parting company with tenders whilst being driven  This seems a far commoner occurrence than any boiler problems. John |
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SteveW
Elder Statesman
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Post by SteveW on Mar 21, 2009 22:33:52 GMT
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Post by havoc on Mar 22, 2009 15:17:10 GMT
Worst "accidents" I heard of here had nothing to do with boilers. More things like passengers pulling the pins in the links between cars, getting their fingers where they don't belong and burned fingers.
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Post by fostergp6nhp on Mar 22, 2009 21:16:48 GMT
The only incident i know of was a 7 1/4" gauge Kerr Stewart Wren with a silver soldered copper boiler belonging to a friend of mine. The owner left his engine in the 'care' of somebody else while he nipped home from the track for his Sunday lunch. The person who was doing the minding had been driving around the track under supervision and deemed responsible enough to leave the engine in his care. When the owner returned it was to find a puzzled carer as the Wren did not want to steam properly for no obvious (to the carer) reason. It turned out to be a dry boiler as the carer had forgotten to put any water in! Result was that the firebox and smokebox tube plates has run the silver soldered joints. Pressure testing revealed a colander in the shape of a boiler. All attempts to re-silver solder the leaks were unsuccesfull despite pickling and the boiler was replaced with a steel job.
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simonwass
Part of the e-furniture
Cecil Pagets 2-6-2 of 1908. Engine number 2299. Would make a fascinating model....
Posts: 472
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Post by simonwass on Mar 22, 2009 22:36:09 GMT
Not wishing so sound like I'm doubting what you wrote, but, smokebox tubeplate SS run? I'd have thought the fire would be long gone after the firebox tubeplate giving up, let alone there being enough steam to allow the blower to cause hot gases to allow the front tubeplate to get to cherry red.
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Post by alanstepney on Mar 23, 2009 8:17:04 GMT
It is almost certainly true that locos parting company with the tender or the rest of the train is far more common than than boiler troubles.
As for kids or even adults (who should know better) putting their fingers in places they shouldnt, that is also a problem, although perhaps more so with the "full size" guys than "us".
As one example, most traction engines now have a guard over the "pinch point" on belt drives.
Reverting to boilers, although I have details of some failures and I expect there have been others that I know nothing about, these may have ruined someone model, but fortunately havent caused serious personal injury or death.
It is that record, an enviable one, that enables us to have low cost insurance, and was a major reason why we are still allowed to build our own boilers.
I would hate to see it change.
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russell
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Post by russell on Mar 23, 2009 9:10:23 GMT
Some very interesting replies.
It would seem that the most common cause of boiler failure (amongst the very few failures) is the result of the firebox crown becoming uncovered. Damage to the boiler in such cases could be avoided by the use of a fusible plug as recommended here (in France) by the CAV.
The incident reported by Styeve W is interesting and it is a shame that he was not able to find out more about the cause.
I am a bit confused (as is often the case) by the fact that "we are still allowed to build our own boilers". There have been statements that this was going to be disallowed and that work went on behind the scenes to give us an exemption but who was going to disallow home construction? The HSE? It was certainly not the EU Directive.
Regards,
Russell.
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Post by havoc on Mar 23, 2009 11:04:13 GMT
I'm afraid the jury is out on that one. In full size fusible plugs were notorious for not working. Biggest problem was scale buildup. Maybe not such a problem for us but I wouldn't expect miracles from it.
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steam4ian
Elder Statesman
One good turn deserves another
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Post by steam4ian on Mar 23, 2009 11:16:06 GMT
G'day Russell.
Your last point means the issues need defining; as I see them they:
1/ What you are allowed to do privately (In most jurisdictions you can't legally brew amphetamines)
2/ What you can sell or trade which comes under EU directives. (There is some discussion about when trade occurs, is it looking over shoulder giving advice? Is it holding a second torch? or is it holding the torch?)
3/ What you can use in a public place (May be governed by local amusement regulations)
4/ What you can use in a work place (Health and Safety Regulations)
5/ What you can insure; this is important to the outcome for 3 & 4 above.
Our boilers are pressure vessels and there are local, national and in your case, international codes covering every aspect of pressure vessel design, manufacture and use.
What we are allowed to do in building our own in UK or Oz is a concession against the strict application of those codes. Hence Alan's comments.
Thankfully in Oz we have a slightly better situation than elsewhere due to our AMBSC Codes.
BTW have I advocated that persons get a copy of the AMBCS codes? they are good reading.
Regards
Ian
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steam4ian
Elder Statesman
One good turn deserves another
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Post by steam4ian on Mar 23, 2009 11:33:57 GMT
G'day Havoc
In full size a fuzible plug failure lead to the death of one person.
The boiler was steaming well with over a half a glass when the entire fusible plug assembly blew out of the crown sheet. The loco was a coal/ oil burner, that is a coal fire was maintained but the real grunt came from two oil burners which protruded through the backhead. When the plug blew out a 50mm diameter jet of steam and water shot down onto the fire. The resultant blast came back into the cab through the oil burner ducts. The loco is relatively modern and had a fully enclosed cab complete with diaphram connection to the tender. The only escape for the hot blast was out the cab doors and the person killed was standing in the door way. The driver and fireman were sitting forward in the cab and missed the direct blast but suffered burns sufficient for hospitalisation; both have recovered.
The plug failed due to over tightening in the crown sheet; apparently it had been weeping and on each inspection a different person had tightened it a bit more until the brass ultimately yielded.
The scary thing is that only a year later another preservation group found that a similar train of events was being set in motion, thankfully it was picked up.
The moral: If something is leaking, find out why, don't just assume it is loose.
Regards,
Ian
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Post by havoc on Mar 23, 2009 11:59:21 GMT
Ian, as fusible plugs were almost always fitted, they did not prevent the accidents where the crown became uncovered. At the belgian railways fusible plugs were replaced at each maintenance washout because of reliability issues: not blowing when they should blow. And each time scale buildup on the inside of the boiler was the problem.
And for models I don't want to experience a fusible plug blowing in an alcohol burner...
Edit: I looked it up in "La Locomotive" by Lamalle & Legein. In Germany the plugs were changed at least every 3 months (Die Dampfloomotive" Transpress) In the book are photos of plugs that blew prematurely. And some typos corrected...
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Gary L
Elder Statesman
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Post by Gary L on Mar 23, 2009 21:45:48 GMT
Out of curiosity, given the size of fire, and the mass of the copper in an typical model boiler, is it physically possible to get it up to silver-soldering temperatures? Even in a completely dry boiler with the lagging on?
I've never made a boiler, but do I know how hard it is to get relatively small lumps of copper hot enough...
BTW, burning alcohol is extinguished with water, unlike burning oil. But getting an alcohol-fired boiler hot enough to melt the lead in a fusible plug also sounds like quite an achievement... has it ever been done?
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Post by fostergp6nhp on Mar 23, 2009 21:52:36 GMT
The Wren boiler failure points was quoted to me by the owner who had made and then tried to repair the boiler.
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Post by peterseager on Mar 23, 2009 22:05:04 GMT
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Post by baggo on Mar 24, 2009 0:22:46 GMT
Sounds like a common fault when boilers are built using only oxy-acetylene gear. Probably no preheat was used so the solder only flows on the surface of the joint with no penetration into the joint itself.
John
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Post by Shawki Shlemon on Mar 24, 2009 6:16:01 GMT
Baggo has a very interesting point , that is why inspection by inspector and not the builder at several stages is necessary to ensure penetration has taken place, however the last stages IE back plate and foundation where it is not possible to see the other side is the problem. to ensure penetration pre heat is required and even using oxy one must apply the heat where the solder is required to go and not on the solder .
As for the fusible plug , I would not have it on my engines . They are not easy to check and maintain and the soft solder deteriorate over period of time and heat and failure is possible without warning and could have devastating effect on the driver or operator.
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Post by peterseager on Mar 24, 2009 19:38:53 GMT
Looking at the photo, I think the warning signs were there if the cladding had been removed. Lots of white deposits around stays.
Peter
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This seems a far commoner occurrence than any boiler problems.
